Thinking past the media's class-envy red herring, let's pretend that the hypothetical third-world country Elbonia gets the vaccine doses to vaccinate half its population:
* Does Elbonia have the regionally located storage facilities that can store the several vaccines at the temperatures they need to be stable for a significant period of time?
* Does Elbonia have the temperature controlled trucks that can maintain the several vaccines at the temperatures they need to be stable during transport?
* Does Elbonia have the medical facilities in the many cities and towns that can properly store the vaccines and people trained to handle and prepare the shots?
* Does Elbonia have the medical/pharmacy people with the training to administer the vaccinations properly and observe the recipients for a reasonable time period for adverse reactions?
The Pfizer vaccine must be stored and transported at the temperature of dry ice - relatively easy in the US or EuroLand, but much less easy in a third world country. The Moderna vaccine is more forgiving, best stored at ordinary freezer temperatures, but in a third world country where freezers are not in every household and power is unreliable (if available)? As the OP article mentions (IIRC), the AstraZeneca vaccine - refrigerator storage temps - is better suited to third world usage, though probably at best it will be the third vaccine to receive FDA EUA, IOW a month or two from now.